Conventionally, as two-part hair bleaches or hair dyes, those in a liquid or cream form have been broadly used from old times. However, it is difficult for unskilled persons to apply these liquid or cream agents to hair without causing unevenness. The viscosity of a mixture to be applied to hair is adjusted to a high value which is approximately 1000 to 10000 mPa·s, so that an agent is prevented from dripping down while it is left for a certain time of period, and thus, it is difficult to uniformly spread the agent, and it is also difficult to allow the agent to sufficiently penetrate into the root of hair. Moreover, in order to apply the agent to the root portion of hair and to the back of the head, skills such as blocking (segmentation of hair) and a two-mirror technique for confirming application of the agent to the hair are required, and a lot of time is also required.
In contrast to such a two-part hair bleach or two-part hair dye, a mixed solution of two-part hair bleaches or two-part hair dyes, which is discharged from a non-aerosol foamer container in the form of foam, has been known (Patent Document 1). In the case of this hair bleach or hair dye, since a mixed solution of a first part and a second part is discharged from a non-aerosol foamer container in the form of foam, even an unskilled person can easily apply the agent to hair without causing unevenness, and color unevenness does not occur at the time of finishing. Since this agent can be easily applied to hair, skills such as blocking and a two-mirror technique are not necessary, and the time required for hair dye is significantly shorter than that in the case of the conventional agent. Hence, since a mixed solution of two-part hair agents has performance much more excellent than the conventional hair agent, it has been supported by a wide range of customers, regardless of sex and age. As such, various products have been developed for the needs of a wide variety of customers.
Moreover, Patent Document 2 discloses a technique of setting a ratio between a surfactant and a higher alcohol mixed into a two-part hair bleach or a two-part hair dye at a specific ratio and thereby improving foaming properties at a low temperature.
(Patent Document 1) JP-A-2004-339216
(Patent Document 2) JP-A-2007-291015